package io.springboot.jpa.examples.springbootjpaexamples.config.shiro;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.util.StringUtils;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.util.WebUtils;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author yzc
 * @description
 * @date 2018/9/26
 */
public class StatelessFilter extends BasicHttpAuthenticationFilter {

    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest httpServletRequest = WebUtils.toHttp(request);
        String token = getToken(httpServletRequest);
        if (StringUtils.hasLength(token)) {
            return true;
        }
        return false;
    }

    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = WebUtils.toHttp(request);
        String token = getToken(httpServletRequest);
        JsonWebToken jsonWebToken = new JsonWebToken(token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jsonWebToken);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest servletRequest, ServletResponse servletResponse, Object o) {

        if (isLoginAttempt(servletRequest, servletResponse)) {
            try {
                executeLogin(servletRequest, servletResponse);
                return true;
            } catch (Exception e) {
                throw new AuthenticationException(e.getMessage());
            }
        }
        return false;
    }

    private String getToken(HttpServletRequest httpServletRequest) {
        String token = httpServletRequest.getHeader("Token");
        if (!StringUtils.hasLength(token)) {
            Cookie[] cookies = httpServletRequest.getCookies();
            if (cookies != null && cookies.length > 0) {
                for (int i = 0; i < cookies.length; i++) {
                    if (cookies[i].getName().equals("Token")) {
                        token = cookies[i].getValue();
                        break;
                    }
                }
            }
        }
        if (!StringUtils.hasLength(token)) {
            token = httpServletRequest.getParameter("Token");
        }
        return token;
    }
}
